CN102876350B - Method and the application thereof of high hexadecane value alkane fuel is prepared by Ru series catalyzer to catalyse vegetables oil or longer chain fatty acid - Google Patents

Abstract

The invention provides a method for preparing high cetane number alkane fuel from vegetable oil and long-chain fatty acid catalyzed by Ru series catalyst, comprising the following steps: (1) mixing vegetable oil or long-chain fatty acid and solvent in proportion; (1) A catalyst with hydrogenation function is added to the mixed liquid; (3) A reaction occurs under a reducing atmosphere to obtain long-chain alkanes whose main composition is C ₁₅ ~C ₁₈ . The fatty acid prepared by the method of catalyzing vegetable oil or long-chain fatty acid with the Ru series catalyst provided by the invention has high conversion rate and high alkane yield. In addition, the method of the invention has simple process, convenient operation, mild reaction conditions, basically no carbon deposition in the whole reaction process, cheap and easy-to-obtain catalyst, and can be repeatedly used without reducing activity. The product of the invention can be directly used as diesel oil, and has important economic and social significance for the sustainable supply of vehicle liquid fuel.

Description

Method for preparing high cetane number alkane fuel by catalyzing vegetable oil or long-chain fatty acid with Ru series catalyst and its application

technical field

The invention relates to the field of fine chemical industry, in particular to a method for preparing high cetane number alkane fuel by catalyzing vegetable oil or long-chain fatty acid with Ru series catalyst and its application.

Background technique

With the development of today's society, energy consumption is increasing rapidly, fossil energy is becoming increasingly exhausted, and the whole world is facing the problem of energy shortage. Renewable resources, as a kind of green energy, have drawn more and more attention from people. Biodiesel is a renewable energy source with great development potential, and its raw materials are mainly vegetable oil, animal fat, and waste cooking oil. Traditionally, biodiesel is prepared by transesterifying oils composed of fatty acids and glycerol into methyl or ethyl ester oxygenates. The biodiesel prepared by this process has high oxygen content and poor fluidity at low temperature. In recent _years , people have paid attention to the technology of directly converting oils into alkanes through _{hydrodeoxygenation} or decarboxylation reactions. The alkane obtained after the decarboxylation process has a higher cetane number and is more suitable for use as fuel. Moreover, the treatment process is simpler, and the discharge of waste liquid and gas is less. At present, the main problems of the direct hydrodeoxygenation or decarboxylation of oils to generate alkanes are high reaction temperature (300~330℃), low catalyst activity, and poor selectivity of C ₁₅ ~C ₁₈ alkanes. The conversion of oils to long-chain alkanes by hydrodecarboxylation under mild conditions can be directly used as diesel oil, which is of great significance for the sustainable supply of liquid fuels for vehicles.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a method for producing long-chain alkanes with high hydrogenation yield and high yield of long-chain alkanes by catalytic conversion of vegetable oil or long-chain fatty acids with Ru-based catalysts.

Another object of the present invention is to provide the application of the above method in the preparation of liquid fuel.

In order to realize the foregoing invention object, the present invention provides a kind of method that prepares high cetane number alkane fuel by Ru series catalyst catalysis vegetable oil or long-chain fatty acid, comprises the steps:

(1) Mix vegetable oil or long-chain fatty acid with solvent in proportion;

(2) Adding a catalyst with hydrogenation function to the mixed liquid in step (1);

(3) Reaction occurs under reducing atmosphere to obtain mainly C ₁₅ ~C ₁₈ alkanes.

Wherein, the vegetable oil in step (1) includes soybean oil, palm oil, cottonseed oil, peanut oil, sunflower oil, rapeseed oil, rice bran oil, corn oil, castor oil, tallow oil, catalpa oil, pistachio oil, tung oil, Jatropha oil, eucalyptus oil, privet oil, olive oil, sapinberry oil, jatropha oil, camelina oil, etc.; long-chain fatty acids include oleic acid, palmitic acid, stearic acid, linoleic acid, flax One or several kinds of oleic acid.

Wherein, the solvent in step (1) is any liquid that is compatible with long-chain fatty acids. Preferably, it is one or more of n-hexane, cyclohexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane and dichloromethane.

The mass ratio of the vegetable oil or long-chain fatty acid to the solvent in step (1) is preferably 1:1-300.

Wherein, the catalyst with hydrogenation function described in step (2) is preferably a Ru-based catalyst, including a catalyst in which Ru is supported on different supports. The presence of Ru makes the catalyst have hydrogenation properties. The mass ratio of the vegetable oil or long-chain fatty acid to the catalyst is preferably 1:0.005~1.

Step (2) also includes adding a catalyst promoter. The catalytic promoter mainly plays a catalytic auxiliary role for the main catalyst, thereby improving the activity and stability of the main catalyst, that is, the ruthenium-based catalyst, and reducing its consumption. For example, the deactivation and carbon deposition of the main catalyst can be prevented.

The catalytic promoter is any one or several elements of Group IIIB, Group IVB or Group IIIA, or an alloy or metal oxide of any one or several elements of Group IIIB, Group IVB or Group IIIA . Group IIIB mentioned therein includes lanthanides and actinides.

The reaction system also includes a catalyst carrier; the catalyst carrier is preferably any one or a group of microporous oxide carrier, mesoporous oxide carrier or activated carbon carrier, such as montmorillonite (MMT), ZSM- 5. HZSM-5, SBA-15, MCM-41, ZrO ₂ , TiO ₂ , SiO ₂ etc.

The reducing atmosphere in step (3) is achieved by adding a reducing gas or a substance capable of producing a reducing gas to the reaction system; the reducing gas is preferably hydrogen, and the substance capable of producing a reducing gas is preferably Formic acid, sodium borohydride or lithium borohydride.

Preferably, the reaction pressure in step (3) is 0.1-20MPa, the temperature is 100-300°C, and the time is 1-24h. .

The present invention also provides the application of the above method in preparing other liquid fuels.

Beneficial effects of the present invention:

The invention provides a method for preparing high cetane number alkane fuel by catalyzing vegetable oil and long-chain fatty acid with a Ru series catalyst, and obtaining long-chain alkane with high conversion rate and high selectivity through hydrogenation catalysis. The method has a high yield of long-chain alkanes. In addition, the method has the advantages of simple process, convenient operation, mild reaction conditions, basically no carbon deposition in the whole reaction process, cheap and easy-to-obtain catalyst, can be repeatedly used, and does not reduce activity.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

Figure 1 is the GC spectrum of long-chain alkanes obtained from oleic acid catalyzed by Ru/TiO ₂ (Experiment No. 3).

Figure 2 is the GC spectrum of long-chain alkanes obtained from soybean oil catalyzed by Ru/MMT (Experiment No. 16).

Detailed ways

Embodiments of the present invention are described in detail below. The embodiments described below are exemplary, and are only for explaining the present invention, and should not be construed as limiting the present invention.

Reactor: 316 stainless steel high-pressure reactor (PARR, 0.05L), high-pressure mechanical stirring tank (zirconium material, Weihai Huixin Chemical Machinery Co., Ltd., GSH-0.1A).

GC: Kexiao 1690, OV1701 capillary column.

GC-MS: Agilent 7890A+Agilent 5975C, DB-5 capillary column.

Example 1

Weigh 0.2g of long-chain fatty acid and mix it with 20ml of solvent (see Table 1 for details), put it into a 50mL reactor, and then put in 0.1g of catalyst (see Table 1 for details). Replace the air in the kettle with hydrogen for three to four times, and then fill it with hydrogen at a certain pressure to minimize the air content in the kettle, especially the oxygen content, so as to maintain the reducing atmosphere in the kettle. Turn on the stirring device to about 1000 rpm, then heat to a certain temperature (see Table 1 for details) and maintain it for a certain period of time. After the reaction was completed, it was cooled to room temperature, and the liquid product was collected. The liquid product was analyzed for its chemical composition by GC-MS and GC. The results are shown in Table 1 for the results of experiments numbered 1-13.

Example 2

Weigh 10g of mixed long-chain fatty acids (5g stearic acid + 5g palmitic acid) and mix with 10mL solvent (see Table 1 for details), put it into a 50mL reactor, and then add 5g of catalyst (see Table 1 for details). Replace the air in the kettle with nitrogen for three to four times, and then fill it with hydrogen at a certain pressure to minimize the air content in the kettle, especially the oxygen content, so as to maintain the reducing atmosphere in the kettle. Turn on the stirring device to about 1000 rpm, then heat to a certain temperature (see Table 1 for details) and maintain it for 24 hours. After the reaction was completed, it was cooled to room temperature, and the liquid product was collected. The liquid product was analyzed for its chemical composition by GC-MS and GC. The results are shown in Table 1, the results of experiment No. 14.

Example 3

Weigh 0.2g mixed long-chain fatty acid (0.1g stearic acid + 0.1g palmitic acid) and mix with 60mL solvent (see Table 1 for details), put it into a 100mL reactor, and then put in 0.1g catalyst (see Table 1 for details ). Replace the air in the kettle with nitrogen for three to four times, and then fill it with hydrogen at a certain pressure to minimize the air content in the kettle, especially the oxygen content, so as to maintain the reducing atmosphere in the kettle. Turn on the stirring device to about 1000 rpm, then heat to a certain temperature (see Table 1 for details) and maintain it for 12 hours. After the reaction was completed, it was cooled to room temperature, and the liquid product was collected. The liquid product was analyzed for its chemical composition by GC-MS and GC. The results are shown in Table 1 for the results of experiment No. 15.

Example 4

Weigh 1g of vegetable oil and mix with 50mL solvent (see Table 1 for details), put it into a 100mL reactor, and then put in 0.5g of catalyst (see Table 1 for details). Replace the air in the kettle with hydrogen for three to four times, and then fill it with hydrogen at a certain pressure to minimize the air content in the kettle, especially the oxygen content, so as to maintain the reducing atmosphere in the kettle. Turn on the stirring device to about 1000 rpm, then heat to a certain temperature (see Table 1 for details) and maintain it for 8 hours. After the reaction was completed, it was cooled to room temperature, and the liquid product was collected. The liquid product was analyzed for its chemical composition by GC-MS and GC. The results are shown in Table 1 for the results of experiments numbered 16-19.

Example 5

Weigh 0.5g vegetable oil and mix with 50mL solvent (see Table 1 for details), put it into a 100mL reactor, and then put in 0.5g catalyst (see Table 1 for details) and 1g formic acid. Replace the air in the kettle with nitrogen three to four times to get rid of the air in the kettle, and finally discharge the nitrogen. Turn on the stirring device to about 1000 rpm, then heat to a certain temperature (see Table 1 for details) and maintain it for 8 hours. After the reaction was completed, it was cooled to room temperature, and the liquid product was collected. The liquid product was analyzed for its chemical composition by GC-MS and GC. The results are shown in Table 1 for the results of experiment No. 20.

The experimental result of table 1 embodiment 1-5

It can be seen from the above results that Ru/TiO ₂ , Ru/SiAl, Ru/MMT, Ru/SiO ₂ etc. all have good catalytic activity. Ru/SiO ₂ and Ru/SiAl catalyze more decarboxylation or decarbonylation products (n-heptadecane or n-pentadecane), while in Ru/MMT catalysis, more hydrodeoxygenation products (n-decane Hexane, n-octadecane).

Figure 1 is the accompanying drawing of Experiment No. 3. It can be seen from the figure that the main product of oleic acid through the action of Ru/ _TiO2 is n-heptadecane, and a small amount of n-octadecane and n-pentadecane are formed. Fig. 2 is the accompanying drawing of No. 16 experiment. It can be seen from the figure that after the soybean oil is processed by this system, long-chain alkanes whose main components are n-pentadecane, n-hexadecane, n-heptadecane and n-octadecane are produced, and almost no other by-products are produced.

In summary, Ru-based catalysts can efficiently catalyze the hydrodeoxygenation of vegetable oils and long-chain fatty acids to corresponding long-chain alkanes under mild conditions.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (5)

1. prepared a method for high hexadecane value alkane fuel by Ru series catalyzer to catalyse vegetables oil or longer chain fatty acid, comprise the steps:

(1) vegetables oil or longer chain fatty acid and solvent is mixed in proportion; Described longer chain fatty acid is oleic acid, palmitinic acid, linolic acid, the one of linolenic acid; The mass ratio of described vegetables oil or longer chain fatty acid and solvent is 1:1 ~ 300; The mass ratio of described vegetables oil or longer chain fatty acid and catalyzer is 1:0.5 ~ 1;

(2) in step (1) mixed solution, add the catalyzer and catalyst aid and support of the catalyst with hydrogenating function; The described catalyzer with hydrogenating function is Ru series catalysts; Described catalyst aid is any one or a few element in IIIA race, or the oxide compound of any one or a few element in described IIIA race, described support of the catalyst is any one or one group of microporous oxide carrier, mesopore oxide carrier or absorbent charcoal carrier;

(3) react under reducing atmosphere, mainly consisted of C ₁₅~ C ₁₈long chain alkane; Described reaction pressure is 0.1 ~ 20MPa, and temperature is 100 ~ 300 DEG C, and the time is 1 ~ 24h; Described reducing atmosphere is that the material that maybe can produce reducing gas by adding reducing gas in reaction system realizes; Described reducing gas is hydrogen.

2. method according to claim 1, is characterized in that, step (1) described vegetables oil comprises soybean oil, plam oil, Oleum Gossypii semen, peanut oil, sunflower seed oil, rapeseed oil, Rice pollard oil, Semen Maydis oil, Viscotrol C, Chinese vegetable tallow, Chinese catalpa oil, coptis wood oil, tung oil, idesia oil, wilson dogwood oil, glossy privet seed oil, sweet oil, Seed of Chinese Soapberry oil, jatropha oil, false flax oil.

3. method according to claim 1, is characterized in that, step (1) described solvent is normal hexane, hexanaphthene, normal heptane, octane, n-nonane, n-decane, n-undecane, n-dodecane, one or more in methylene dichloride.

4. method according to claim 1, is characterized in that, the described material that can produce reducing gas is formic acid, sodium borohydride or lithium borohydride.

5. method described in Claims 1 to 4 any one is preparing the application in liquid fuel.